Radio frequency (RF) interference can disrupt reception of a desired signal. To reduce the impact of interference, many governmental entities have established standards and regulations to limit the transmission bandwidth of RF transmitters having an output power in excess of a predetermined level. For example, in the United States, long range RF transmissions are regulated by the Federal Communications Commission (FCC) and in Europe, the European Telecommunications Standards Institute (ETSI) proposes standards for consideration and implementation by individual countries.
In general, the telemetry system of an implantable medical device includes a near field inductive coil. Typically, the near field telemetry system does not generate far field RF interference and thus, can operate in compliance with standards and regulations. On the other hand, near field telemetry systems do not allow long range communication between the implanted device and an external programmer.
What is needed is a long range telemetry system suitable for use with an implantable medical device that conforms to standards and regulations limiting RF interference.